mkxp/src/vorbissource.cpp

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2014-07-23 15:28:20 +00:00
/*
** vorbissource.cpp
**
** This file is part of mkxp.
**
** Copyright (C) 2014 Jonas Kulla <Nyocurio@gmail.com>
**
** mkxp is free software: you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation, either version 2 of the License, or
** (at your option) any later version.
**
** mkxp is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with mkxp. If not, see <http://www.gnu.org/licenses/>.
*/
#include "aldatasource.h"
#include "exception.h"
#define OV_EXCLUDE_STATIC_CALLBACKS
#include <vorbis/vorbisfile.h>
#include <vector>
#include <algorithm>
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static size_t vfRead(void *ptr, size_t size, size_t nmemb, void *ops)
{
return SDL_RWread(static_cast<SDL_RWops*>(ops), ptr, size, nmemb);
}
static int vfSeek(void *ops, ogg_int64_t offset, int whence)
{
return SDL_RWseek(static_cast<SDL_RWops*>(ops), offset, whence);
}
static long vfTell(void *ops)
{
return SDL_RWtell(static_cast<SDL_RWops*>(ops));
}
static ov_callbacks OvCallbacks =
{
vfRead,
vfSeek,
0,
vfTell
};
struct VorbisSource : ALDataSource
{
SDL_RWops &src;
OggVorbis_File vf;
uint32_t currentFrame;
struct
{
uint32_t start;
uint32_t length;
uint32_t end;
bool valid;
bool requested;
} loop;
struct
{
int channels;
int rate;
int frameSize;
ALenum alFormat;
} info;
std::vector<int16_t> sampleBuf;
VorbisSource(SDL_RWops &ops,
bool looped)
: src(ops),
currentFrame(0)
{
int error = ov_open_callbacks(&src, &vf, 0, 0, OvCallbacks);
if (error)
{
SDL_RWclose(&src);
throw Exception(Exception::MKXPError,
"Vorbisfile: Cannot read ogg file");
}
/* Extract bitstream info */
info.channels = vf.vi->channels;
info.rate = vf.vi->rate;
if (info.channels > 2)
{
ov_clear(&vf);
SDL_RWclose(&src);
throw Exception(Exception::MKXPError,
"Cannot handle audio with more than 2 channels");
}
info.alFormat = chooseALFormat(sizeof(int16_t), info.channels);
info.frameSize = sizeof(int16_t) * info.channels;
sampleBuf.resize(STREAM_BUF_SIZE);
loop.requested = looped;
loop.valid = false;
loop.start = loop.length = 0;
if (!loop.requested)
return;
/* Try to extract loop info */
for (int i = 0; i < vf.vc->comments; ++i)
{
char *comment = vf.vc->user_comments[i];
char *sep = strstr(comment, "=");
/* No '=' found */
if (!sep)
continue;
/* Empty value */
if (!*(sep+1))
continue;
*sep = '\0';
if (!strcmp(comment, "LOOPSTART"))
loop.start = strtol(sep+1, 0, 10);
if (!strcmp(comment, "LOOPLENGTH"))
loop.length = strtol(sep+1, 0, 10);
*sep = '=';
}
loop.end = loop.start + loop.length;
loop.valid = (loop.start && loop.length);
}
~VorbisSource()
{
ov_clear(&vf);
SDL_RWclose(&src);
}
int sampleRate()
{
return info.rate;
}
void seekToOffset(float seconds)
{
if (seconds <= 0)
{
ov_raw_seek(&vf, 0);
currentFrame = 0;
}
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currentFrame = seconds * info.rate;
if (loop.valid && currentFrame > loop.end)
currentFrame = loop.start;
/* If seeking fails, just seek back to start */
if (ov_pcm_seek(&vf, currentFrame) != 0)
ov_raw_seek(&vf, 0);
}
Status fillBuffer(AL::Buffer::ID alBuffer)
{
void *bufPtr = sampleBuf.data();
int availBuf = sampleBuf.size();
int bufUsed = 0;
int canRead = availBuf;
Status retStatus = ALDataSource::NoError;
bool readAgain = false;
if (loop.valid)
{
int tilLoopEnd = loop.end * info.frameSize;
canRead = std::min(availBuf, tilLoopEnd);
}
while (canRead > 16)
{
long res = ov_read(&vf, static_cast<char*>(bufPtr),
canRead, 0, sizeof(int16_t), 1, 0);
if (res < 0)
{
/* Read error */
retStatus = ALDataSource::Error;
break;
}
if (res == 0)
{
/* EOF */
if (loop.requested)
{
retStatus = ALDataSource::WrapAround;
seekToOffset(0);
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}
else
{
retStatus = ALDataSource::EndOfStream;
}
/* If we sought right to the end of the file,
* we might be EOF without actually having read
* any data at all yet (which mustn't happen),
* so we try to continue reading some data. */
if (bufUsed > 0)
break;
if (readAgain)
{
/* We're still not getting data though.
* Just error out to prevent an endless loop */
retStatus = ALDataSource::Error;
break;
}
readAgain = true;
}
bufUsed += (res / sizeof(int16_t));
bufPtr = &sampleBuf[bufUsed];
currentFrame += (res / info.frameSize);
if (loop.valid && currentFrame >= loop.end)
{
/* Determine how many frames we're
* over the loop end */
int discardFrames = currentFrame - loop.end;
bufUsed -= discardFrames * info.channels;
retStatus = ALDataSource::WrapAround;
/* Seek to loop start */
currentFrame = loop.start;
if (ov_pcm_seek(&vf, currentFrame) != 0)
retStatus = ALDataSource::Error;
break;
}
canRead -= res;
}
if (retStatus != ALDataSource::Error)
AL::Buffer::uploadData(alBuffer, info.alFormat, sampleBuf.data(),
bufUsed*sizeof(int16_t), info.rate);
return retStatus;
}
uint32_t loopStartFrames()
{
if (loop.valid)
return loop.start;
else
return 0;
}
bool setPitch(float)
{
return false;
}
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};
ALDataSource *createVorbisSource(SDL_RWops &ops,
bool looped)
{
return new VorbisSource(ops, looped);
}